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  • Question
  • What will be the output of the program?
    String a = "ABCD"; 
    String b = a.toLowerCase(); 
    b.replace('a','d'); 
    b.replace('b','c'); 
    System.out.println(b);
    


  • Options
  • A. abcd
  • B. ABCD
  • C. dccd
  • D. dcba

  • Correct Answer
  • abcd 

    Explanation
    String objects are immutable, they cannot be changed, in this case we are talking about the replace method which returns a new String object resulting from replacing all occurrences of oldChar in this string with newChar.

    b.replace(char oldChar, char newChar);

    But since this is only a temporary String it must either be put to use straight away i.e.

    System.out.println(b.replace('a','d'));

    Or a new variable must be assigned its value i.e.

    String c = b.replace('a','d');


    Java.lang Class problems


    Search Results


    • 1. What will be the output of the program?
      public class BoolTest 
      {
          public static void main(String [] args) 
          {
              int result = 0;
      
              Boolean b1 = new Boolean("TRUE");
              Boolean b2 = new Boolean("true");
              Boolean b3 = new Boolean("tRuE");
              Boolean b4 = new Boolean("false");
      
              if (b1 == b2)  /* Line 10 */
                  result = 1;
              if (b1.equals(b2) ) /* Line 12 */
                  result = result + 10;
              if (b2 == b4)  /* Line 14 */
                  result = result + 100;
              if (b2.equals(b4) ) /* Line 16 */
                  result = result + 1000;
              if (b2.equals(b3) ) /* Line 18 */
                  result = result + 10000;
      
              System.out.println("result = " + result);
          }
      }
      

    • Options
    • A. 0
    • B. 1
    • C. 10
    • D. 10010
    • Discuss
    • 2. What will be the output of the program?
      String a = "newspaper";
      a = a.substring(5,7);
      char b = a.charAt(1);
      a = a + b;
      System.out.println(a);
      

    • Options
    • A. apa
    • B. app
    • C. apea
    • D. apep
    • Discuss
    • 3. What will be the output of the program?
      public class Test 
      { 
          public static void main(String[] args) 
          {
              final StringBuffer a = new StringBuffer(); 
              final StringBuffer b = new StringBuffer(); 
      
              new Thread() 
              { 
                  public void run() 
                  {
                      System.out.print(a.append("A")); 
                      synchronized(b) 
                      { 
                          System.out.print(b.append("B")); 
                      } 
                  } 
              }.start(); 
                  
              new Thread() 
              {
                  public void run() 
                  {
                      System.out.print(b.append("C")); 
                      synchronized(a) 
                      {
                          System.out.print(a.append("D")); 
                      } 
                  } 
              }.start(); 
          } 
      }
      

    • Options
    • A. ACCBAD
    • B. ABBCAD
    • C. CDDACB
    • D. Indeterminate output
    • Discuss
    • 4. What will be the output of the program?
      public class ExamQuestion7 
      {  
          static int j; 
          static void methodA(int i)
          {
              boolean b; 
              do
              { 
                  b = i<10 | methodB(4); /* Line 9 */
                  b = i<10 || methodB(8);  /* Line 10 */
              }while (!b); 
          } 
          static boolean methodB(int i)
          {
              j += i; 
              return true; 
          } 
          public static void main(String[] args)
          {
              methodA(0); 
              System.out.println( "j = " + j ); 
          } 
      }
      

    • Options
    • A. j = 0
    • B. j = 4
    • C. j = 8
    • D. The code will run with no output
    • Discuss
    • 5. What will be the output of the program?
      String x = new String("xyz");
      String y = "abc";
      x = x + y;
      
      How many String objects have been created?

    • Options
    • A. 2
    • B. 3
    • C. 4
    • D. 5
    • Discuss
    • 6. What will be the output of the program?
      public class SqrtExample 
      {
          public static void main(String [] args) 
          {
              double value = -9.0;
              System.out.println( Math.sqrt(value));
          }
      }
      

    • Options
    • A. 3.0
    • B. -3.0
    • C. NaN
    • D. Compilation fails.
    • Discuss
    • 7. What will be the output of the program?
      interface Foo141 
      { 
          int k = 0; /* Line 3 */
      } 
      public class Test141 implements Foo141 
      {
          public static void main(String args[]) 
          {
              int i; 
              Test141 test141 = new Test141(); 
              i = test141.k; /* Line 11 */
              i = Test141.k; 
              i = Foo141.k; 
          } 
      }
      

    • Options
    • A. Compilation fails.
    • B. Compiles and runs ok.
    • C. Compiles but throws an Exception at runtime.
    • D. Compiles but throws a RuntimeException at runtime.
    • Discuss
    • 8. What will be the output of the program?
      class Q207 
      { 
          public static void main(String[] args) 
          {
              int i1 = 5; 
              int i2 = 6; 
              String s1 = "7"; 
              System.out.println(i1 + i2 + s1); /* Line 8 */
          } 
      }
      

    • Options
    • A. 18
    • B. 117
    • C. 567
    • D. Compiler error
    • Discuss
    • 9. What will be the output of the program?
      String s = "hello"; 
      Object o = s; 
      if( o.equals(s) )
      {
          System.out.println("A"); 
      } 
      else
      {
          System.out.println("B"); 
      } 
      if( s.equals(o) )
      {
          System.out.println("C"); 
      } 
      else
      { 
          System.out.println("D"); 
      }
      
      1. A
      2. B
      3. C
      4. D

    • Options
    • A. 1 and 3
    • B. 2 and 4
    • C. 3 and 4
    • D. 1 and 2
    • Discuss
    • 10. What will be the output of the program?
      public class ObjComp 
      {
          public static void main(String [] args ) 
          {
              int result = 0;
              ObjComp oc = new ObjComp();
              Object o = oc;
      
              if (o == oc)  
                  result = 1;
              if (o != oc)  
                  result = result + 10;
              if (o.equals(oc) )  
                  result = result + 100;
              if (oc.equals(o) )  
                  result = result + 1000;
      
              System.out.println("result = " + result);
          }
      }
      

    • Options
    • A. 1
    • B. 10
    • C. 101
    • D. 1101
    • Discuss


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